A conventional plasma etching apparatus performs etching using a photoresist as a mask. There has been a method of depositing deposits on a surface of photoresist used as a mask by a plasma etching apparatus. For example, there is a method in which a silicon-containing deposit is deposited on a surface of a photoresist while applying a negative DC voltage to an upper electrode containing silicon.
See, for example, Japanese Patent Laid-Open No. 2007-180358.
However, in the conventional technology, when etching is performed using the photoresist in which the silicon-containing deposit is deposited as a mask, there is a problem that the width of a line formed by etching becomes narrowed and the height of the remaining photoresist is decreased.